Blood Clearance of Radiolabeled Gold Colloid by the Turkey Mononuclear Phagocytic System

Radiolabeled gold colloid (198Au), which has been used to assess particle clearance in mammalian species, was used to assess blood-borne particle clearance in turkeys. When turkeys 16 weeks of age were injected intravenously with these particles, there was greater than a 98% decrease in blood gamma emission from 1 minute to 6 minutes postinjection. Uptake of particles was predominantly hepatic with minor uptake by the spleen and bone marrow. Negligible uptake was observed in lung, kidney, and skeletal muscle. Autoradiography demonstrated particles within Kupffer cells of the liver, periarteriolar macrophages of the spleen, and bone-marrow macrophages. Particles could not be demonstrated within the lung or kidney. The mononuclear phagocyte system responsible for blood particle clearance in turkeys is therefore located predominantly within the liver, spleen, and bone marrow and is similar to that of rats, mice, rabbits, and dogs. Pulmonary intravascular macrophages, which have recently been described in ruminants and pigs, are not apparent in this species.